1. Field of the Invention
The present invention relates to an image forming apparatus, an image forming system including the image forming apparatus, a control method thereof, and storage medium.
2. Description of the Related Art
In recent years, with growing awareness of environmental issues, power saving has been promoted in image forming apparatuses such as printers and multi-function peripherals. One of the practical power saving methods is to control an image forming apparatus to shift it to a power saving mode when it is not used for a long time.
In this case, the power saving mode is one of a plurality of power modes of the image forming apparatus and a state in which the power consumption is smaller than that in a normal state. In this power saving mode, the image forming apparatus often achieves lower power consumption by stopping the supply of power to main control units excluding a RAM, NIC (Network Interface Card), and operation unit. The use of a proxy response function is conceivable in which, when the image forming apparatus receives a packet from a network in this power saving mode, responding to the packet with the NIC to which power is supplied. For example, Japanese Patent Laid-Open No. 2000-165419 discloses a technique of, while an image forming apparatus on a network is in the power saving mode, the NIC of another image forming apparatus in a non-power saving mode responds by proxy to an inquiry to the image forming apparatus in the power saving mode.
In the above conventional arrangement, the first image forming apparatus which performs proxy response is connected to the second image forming apparatus which requests the proxy response via a network. When the second image forming apparatus which has requested proxy response starts up to change its status, the apparatus responds by itself without proxy response.
A technique of connecting an image forming apparatus to a network via a print server is also conceivable. In this case, the print server which receives a packet addressed to the image forming apparatus from a PC or the like on the network performs proxy response for the image forming apparatus. In this case, after the print server shifts to the power saving mode, the image forming apparatus may singly start up to execute an offline job such as copying or scanning without the intervention of the print server. In such a case, the print server stays in the power saving mode unless a packet is received, and hence cannot communicate with the image forming apparatus. That is, the latest state of the image forming apparatus is not sent to the print server. This produces a difference between the current device state of the image forming apparatus connected to the print server and the device state of the image forming apparatus which is stored in the print server which performs proxy response.